In the history of mankind, only a few have been specially selected to serve God from the womb. These have been chosen for a specific work. For example: Isaiah 49:5, "And now the LORD says, Who formed Me from the womb to be His Servant, To bring Jacob back to Him, So that Israel is gathered to Him (For I shall be glorious in the eyes of the LORD, And My God shall be My strength)," This is referring to Christ.
The prophet Jeremiah was called and sanctified from the womb. Jeremiah 1:5, "Before I formed you in the womb I knew you; Before you were born I sanctified you; I ordained you a prophet to the nations." Sanctified means to be holy or set apart for a holy service. The vast majority of mankind have not been set apart by God to serve Him in a specific service.
John the Baptist was chosen even before conception. Luke 1:13-16, "…Elizabeth will bear you a son, and you shall call his name John…For he will be great in the sight of the Lord, and shall drink neither wine nor strong drink. He will also be filled with the Holy Spirit, even from his mother's womb. And he will turn many of the children of Israel to the Lord their God." John was sanctified from the womb to prepare Israel for Messiah.
Finally, God sanctified the apostle Paul from the womb. Galatians 1:15 (NKJV), "But when it pleased God, who separated me from my mother's womb and called me through His grace…" Saul (before he became Paul) must have been consecrated to serve God from birth. He must have maintained a clear conscience always desiring to serve God. He erred in that he did not understand God's plan. When God corrected Saul's comprehension by physically blinding him, Saul's sanctified heart maintained obedience and he changed his service.
God has sometimes chosen a few evil people to fulfill His purposes. Consider Romans 9:17, "For the Scripture says to Pharaoh, 'For this very purpose I raised you up, to demonstrate my power in you, and that my name might be proclaimed throughout the whole earth.'" God over-ruled that this particular man should become the pharaoh of Egypt. Why? Because God knew that that man was stubborn, arrogant, and very powerful. God wanted to demonstrate to the whole world that Pharaoh's power was nothing and could not thwart God's omnipotent purposes. God would deliver His children, Israel.
Mankind is certainly not serving God now. People are not obeying God and are not sanctified to a specific holy work. However, in the ages to come (after Christ's 1000 year reign on earth), doubtless, God will continue to choose (from those already living) specific ones for specific holy services. We truly have no idea how wonderful it will be when all will love God and be devoted to Him.